1. Field of the Invention
The present invention relates to a light-quantity control apparatus installed in optical apparatuses such as image capturing apparatuses and interchangeable lenses.
2. Description of the Related Art
It is desirable that a shape of a stop aperture as a light-passing aperture formed in such a light-quantity control apparatus (aperture stop apparatus) be a circle as closely as possible. For this reason, three or more multiple stop blades (light-quantity control blade) are often used in the light-quantity control apparatus in order to form a stop aperture whose shape is close to the circle.
Japanese Utility Model Laid-Open No. H2-48928 discloses an iris aperture stop apparatus that causes a driving ring rotatable around a fixed aperture formed in a base member to rotate multiple stop blades to form a stop aperture whose shape is a polygon close to the circle.
However, in the iris aperture stop apparatus disclosed in Japanese Utility Model Laid-Open No. H2-48928, a load generated by overlapping of the stop blades may be excessively large.